Understanding the Genetics of Pituitary Tumors

Most pituitary tumors don’t run in families, but about 1 in 20 do. Having a family member with a pituitary tumor doesn’t mean you’ll develop one. But if you have the same genetic mutation, you’re at greater risk.

Learning that a family member has a pituitary tumor may bring up feelings of worry and uncertainty. You may also be concerned about your own risk.

A pituitary tumor forms when cells grow abnormally in your pituitary gland, which sits at the base of your skull. Even though it’s just the size of a bean, some call it the “master control gland” because it controls the hormones other glands make to keep your body running smoothly. Most pituitary tumors are benign (noncancerous).

Most people who develop pituitary tumors don’t have a family history. When they do, it’s usually part of a more significant condition.

Here’s what to know about pituitary tumor causes, related conditions, and the role genetics can play.

People who develop pituitary tumors rarely have family members who have or had them. According to the International Neuroendocrine Cancer Alliance, only about 1 in 20 pituitary tumors have a family link. In these cases, a genetic mutation that increases the risk of a pituitary tumor passes from one generation to the next.

These mutations typically increase your risk of several different tumor types or conditions. In some cases, the mutation seems only to cause pituitary tumors.

Let’s take a look at both scenarios.

FIPA is when a genetic mutation runs in a family but is only associated with pituitary tumors. FIPA accounts for about 2% of all pituitary tumors.

In about 80% of families with FIPA, scientists have yet to identify the gene that causes the mutation.

The most common known mutation is in the aryl hydrocarbon receptor interacting protein (AIP) gene. About 1 in 5 families with FIPA have a mutation in this gene. Still, not everyone with an AIP gene mutation develops FIPA.

Rarely, FIPA may be due to a mutation in the G protein coupled receptor (GPR101) gene on the X chromosome.

It’s more common for people to develop a pituitary tumor as part of a broader genetic condition, also known as a family syndrome. These syndromes typically increase your risk of different conditions or tumor types.

That means the syndrome may show up in different ways in different family members. Some family members may have pituitary tumors, but others may have adrenal, thyroid, or brain tumors, for example.

Some of the genetic conditions associated with pituitary tumors include:

Multiple endocrine neoplasia type 1 (MEN1)

Researchers think a mutation in the MEN1 gene causes the condition. People with MEN1 have an increased risk of pituitary, pancreas, and parathyroid tumors. A parent with this mutation has a 50% chance of passing it on to their children.

Multiple endocrine neoplasia type 4 (MEN4)

MEN4 is similar to MEN1 but is caused by changes to a different gene, CDKN1B. The changes are most often inherited.

Carney complex

People usually inherit Carney complex from one parent. It may involve changes to the PRKAR1A gene.

Carney complex features unusual skin pigmentation, such as flat brown spots on light skin or slightly raised, dark papules on dark skin. Heart, pituitary, or nerve tumors called schwannomas are also part of it.

McCune-Albright syndrome

McCune-Albright syndrome affects endocrine glands, including the pituitary, and produces bone lesions and unusual skin pigmentation.

Familial acromegaly

Pituitary gland problems can cause your body to produce too much growth hormone, causing acromegaly. It can be part of MEN1 or occur by itself within a family. It causes your bones and soft tissue to grow too much.

Other syndromes

Rarely , pituitary cancers may be due to other family syndromes, such as:

• Dicer syndrome
• Lynch syndrome
• hereditary paraganglioma
• neurofibromatosis type 1
• tuberous sclerosis

At what age do pituitary tumors develop?

It’s hard to say when pituitary tumors most commonly begin. Most are slow-growing, taking decades to develop before causing enough problems for a diagnosis. They’re scarce in children but are the most common form of brain tumor diagnosed in people ages 15 to 19.

FIPA may develop earlier than other pituitary tumors. The average age of diagnosis for FIPA is 24 years . About 7 in 8 people experience symptoms of FIPA before they turn 30.

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If you have a family syndrome linked to pituitary tumors, your risk may be greater. It also depends on the syndrome. According to 2020 research , pituitary tumors develop in:

• 40% of people with MEN1
• 20% of people with McCune-Albright syndrome
• 15% of people with Carney complex

If you have a family history of FIPA, your risk might depend on which gene is responsible for the condition. About 20% of people with a mutation in the AIP gene develop pituitary tumors. But about 85% of people with the rare GPR101 gene mutation will develop pituitary tumors.

If you have a family history of pituitary tumors, consider talking with a healthcare professional about genetic testing.

While doctors diagnose about 13,770 people with pituitary tumors each year, very few of these tumors are cancerous. Still, as many as 1 in 4 people with pituitary tumors don’t know they have them because they’re so small.

Anyone can develop a pituitary tumor, but they’re more common in:

• people ages 50 to 75
• women
• Black people
• Hispanic people
• people with certain genetic conditions

Pituitary tumors in Black people

According to 2017 research , Black people in the United States ages 15 to 39 are more likely to have pituitary tumors than white people the same age. After age 40, they’re more than twice as likely to get them as their white counterparts.